The present invention relates to a high-density blindmate optoelectronic module and mating optical connector. The high-density blindmate optoelectronic module is particularly well suited for use in high capacity optical network assemblies, such as optical routers, Dense Wavelength Division Multiplexed (DWDM) transmission equipment, and optical cross connects.
The above-named optical assemblies, and others like them, require numerous interconnections between various components within the assemblies. Typically, multiple optical transmitters and receivers are required for converting data signals between electrical and optical transmission media. A simplified perspective view of a typical prior art chassis based system is shown in FIG. 1. The chassis based system 100 includes a rack 102 comprising a plurality of tracks 104 extending perpendicularly from a backplane 106. The rack 102 is configured to receive a plurality of printed circuit boards 108. The printed circuit boards 108 may be inserted into tracks 104 and mated with connectors 110 mounted on the backplane 106. Most such assemblies include racks for receiving large numbers of removable printed circuit boards. The backplane 106 is configured to route signals between various optical and/or electrical circuits formed on the circuit boards 108 inserted into the rack.
The backplane 106 may include embedded optical fibers for carrying optical signals, conductive traces for carrying electrical signals, or some combination of both optical fibers and conductive traces for handling both optical and electrical signals. The optical and/or electrical circuits on the backplane couple signals between various points within the chassis based system, and may perform additional functions such as amplifying, splitting or multiplexing signals. Signals may be routed between printed circuit boards, or to different points on the same circuit board.
The interface between the printed circuit boards 108 and the backplane 106 is formed along the rear edge of the printed circuit boards as the boards are inserted into the rack. The interface is formed by the act of inserting the printed circuit board into the rack. This is known in the art as a blindmate connection because the connector components that form the interface align and mate of their own accord when the printed circuit board is installed in the rack and the interface occurs within the rack, away from the technician installing the printed circuit board. In such a connector, the signal interface must automatically couple each signal that is to be transmitted from the printed circuit board to the appropriate backplane circuit, be it an optical fiber or a conductive circuit trace. Similarly, each signal originating from the backplane and destined for a circuit formed on the circuit board must also be properly coupled with the correct circuit elements on the printed circuit board. All of this must be achieved by the simple act of inserting the printed circuit board into the rack.
The necessity of providing a blindmate connection between the removable circuit boards and the backplane poses significant difficulties for creating an optical interface capable of handling a large number of optical signals. The current generation of optoelectronic assemblies use fiber-optic connectors mounted on both the backplane and along the rear edge of the removable printed circuit boards. Fiber-optic connectors employed for this purpose may use single fiber connector ferrules or multi-fiber connector ferrules. Typically, optoelectronic modules will be mounted on the surface of a printed circuit board and optical fiber jumpers will be installed between the transceivers and the optical connectors mounted on the edge of the circuit board. The jumpers carry the optical signals emitted from the optical transmitters to the optical connector or from the connector to the optical receivers mounted elsewhere on the printed circuit board. A problem with this arrangement is that the optical transmitters and receivers (commonly referred to together as transceivers) take up a great deal of real estate on the printed circuit board, occupying space which could otherwise be dedicated to other purposes and provide additional functionality to the printed circuit board. Also, installing the optical fiber jumpers between the transceiver elements and the connector interface is time-consuming and expensive. The additional jumper attenuates the optical signal and adds to the cost.
Therefore, a need exists for a high-density blindmate optoelectronic module. Preferably, such a high-density blindmate optoelectronic module will include optical transmitters and receivers mounted directly within the module. The transceiver components will be arranged so that optical signals both transmitted and received by the module may be coupled directly to the backplane of a chassis based system, and the interface between the module and the backplane connector will form a blindmate optical connection whereby the high-density blindmate optoelectronic module is coupled to the backplane by sliding the printed circuit board on which the module is mounted into the chassis based system's support rack. It is desirable that such a high-density blindmate optoelectronic module occupy as little space as possible on the printed circuit board. It is also desirable that signals be directly coupled between the module's optical interface and the backplane without the need for optical fiber jumpers. Finally, it is also desirable that a high-density optoelectronic interface module have improved heat dissipation characteristics to protect the transceiver components within the module.